Petroleum System Modelling of the Vlaming Sub-Basin and Mentelle Basin, Offshore South-Western Australia
Volkmar Neumann1, Rolando di Primio3, Brian Horsfield3, Irina Borissova2, Chris Nicholson2, and Andrew Krassay2
1GeoS4 GmbH, Michendorf, Germany
2Geoscience Australia, Canberra, ACT, Australia
3GFZ-Potsdam, Potsdam, Germany
Basin evolution of the Vlaming Sub-basin and the deep-water Mentelle Basin, both located offshore on the southwest Australian continental margin, were investigated using 2D and 3D petroleum system modelling. The Vlaming Sub-basin has a proven petroleum system with a non-commercial oil discovery at Gage Roads. Exploration activity in this area is limited and has mainly focused on structural highs/tilted fault blocks. The deep-water Mentelle Basin represents frontier exploration acreage but is assumed to have sedimentary facies and source potential similar to the Vlaming Sub-basin.
The Permian-Cenozoic Vlaming Sub-basin contains predominantly siliciclastic fluvial-deltaic, and some marine rocks, reaching up to 14 km in thickness. The Mentelle Basin formed during the break-up of eastern Gondwana, and contains more than 8 km of sedimentary section.
Compositional kinetics, determined on the main source sequences, were used to predict timing of hydrocarbon generation and migration as well as GOR evolution and phase behaviour in our 2D and 3D basin models. The main phase of petroleum generation in the Vlaming Sub-basin occurred at 150 Ma and ceased following inversion and erosion episodes associated with breakup ~ 140Ma. Only the areas that experienced later burial have generated additional hydrocarbons during the Tertiary and up to the present day. Our results indicate the likely generation and trapping of light oils from Jurassic sources with a variety of structural traps. It is these areas that are of greatest interest from an exploration point of view.
The 2D numerical simulations in the Mentelle Basin indicate the presence of an active hydrocarbon generating kitchen. Burial histories and generalized petroleum history will be presented.
AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery